In an internal combustion engine, if valve overlap occurs when a pressure inside an intake port is higher than a pressure inside an exhaust port, air is blown from an intake passage through a cylinder to an exhaust passage, that is, “scavenging” occurs. In an internal combustion engine which is provided with a supercharger such as a turbocharger, scavenging is used when an amount of intake air is insufficient for a torque demand. Due to the occurrence of scavenging, the amount of exhaust gas which sweeps through increases and a speed of a turbine of the supercharger is raised. As a result, a pressure of the intake air is raised and the amount of intake air is made to increase.
Known in the past has been an internal combustion engine which comprises an air-fuel ratio sensor in an exhaust passage of the internal combustion engine and which controls the amount of fuel which is fed to a combustion chamber of the internal combustion engine so that the output of this air-fuel ratio sensor matches a target air-fuel ratio (for example stoichiometric air-fuel ratio (14.6)) (for example, see PLTs 1 and 2).